GB994468A - Apparatus for the preparation of laboratory test samples - Google Patents

Abstract

994,468. Syringes; raising liquids. T. V. FEICHTMEIR. Sept. 30, 1961, No. 35449/61. Heading F1R. [Also in Division B1] Apparatus 20 (see Division B1 for measurement and dilution of a liquid sample comprises calibrated pipette 43 for measuring liquid syringe 32 with variable volume chamber 31 to measure and hold said diluent, and stopcock valve means 24 connected to a vacuum source and operative in one position to fill said pipette and variable volume chamber, and in another position to discharge diluent from said chamber through said pipette. As shown in Fig. 1, to which the above numerals refer, syringe 32 is calibrated and contains plunger 35. Stopcock plug 38 is provided with a parallel pair of diametrically opposed passages 61 and 62 which when vertically disposed connect stub 41 and said syringe to stub 42, and diluent reservoir 33, and stub 39 to pipette 43, plug 38 also having passages 63 in a plane transverse to that of passages 61 and 62 and extending obliquely so that (as shown in Fig. 3) on rotation of the stopcock it connects stub 41 to pipette 43. In operation the stopcock is disposed in the position of Fig. I and the syringe and pipette filled; on rotation to the position of Fig. 3 and operation of plunger 35 the diluent washes the sample from the pipette. These operations may be performed automatically by the apparatus of Fig. 5, in which plunger 98 is operated by piston 103 mounted in cylinder 101 with ports 122 and 123 lying respectively above and below said piston in all positions thereof, each port being alternately vented and connected to a vacuum source by means of valve portion 83 of unit 82, and being connected thereto via tubing 126 and stub 124 and tubing 128 and stub 127 respectively. Stubs 129 and 131 are connected to the source of vacuum and to the atmosphere respectively. Passages 132 and 133 are provided in the plug and arranged so that in the first operative position (see Fig. 6 not shown) passage 132 connects vacuum stub 129 via stub 127 to port 123, and passage 133 connects vent stub 131 via stub 124 to port 122, enabling said pipette and syringe to be filled. On rotation to the position shown in Fig. 10, passage 133 connects vent stub 131 to port 123 and passage 132 connects vacuum stub 129 to port 122, causing said plunger to force diluent from the chamber through the pipette.